Debolina Ghosh, Hathaway Brown High School, Shaker Heights, Ohio, USA

Bitter Melon (Mormodica charantia) Popular in Southern Asia Used mainly for culinary purposes Claimed to work against diabetes, cancer, and

cardiovascular diseases Substance responsible for regulating the body

metabolism and transporting glucose from blood into the cells

Africa: Gastrointestinal parasitic disease treatment

Anecdotal antimalarial and antiviral properties

Infection: bacteria, viruses, or fungi invade body tissues and produce inflammation and tissue damage

Bacteria Gram positive: thick cell wall, 50-90% peptidoglycan Gram negative: thin cell wall, 10% peptidoglycan

Antibiotics Bactericidal: kill the bacteria damaging cell wall/

membrane or altering necessary bacterial enzymes. Bacteriostatic: inhibit the active growth of the bacteria

without killing them

Bacteria: Gram +ve: Staphylococcus aureus

has golden yellow hue-skin infections, pneumonia, sepsis

Gram -ve: Escherichia coli-GI problems, sepsis

Antibiotics: Bactericidal against gram +ve: Penicillin Bacteriostatic against gram +ve: Erythromycin Bactericidal/bacteriostatic against gram -ve: Gentamicin

http://faculty.ccbcmd.edu/courses/bio141/labmanua/lab16/gramstain/gnrod.html

http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit3/bacpath/diseases/staphaureus/gpstaph.html

Bitter melon contains glycosides, terpenoids, and momordicin-1 Momordicin-1 inhibits production of ribosomal

proteins, therefore may have bacteriostatic activity Has chemical that inhibits 30s ribosomal protein,

similar to aminoglycosides like Gentamicin (effective against gram negative bacteria)

Hypothesis: bitter melon extract will either kill or inhibit growth of bacteria (gram positive or negative)

To examine if bitter melon has any antibacterial property

If it has antibacterial property, to see the effect on gram positive and/or gram negative bacteria

To know whether the antibacterial effect is through bactericidal or bacteriostatic mechanism

Bitter melon extracts prepared from interior core, middle, and exterior skin after homogenization and dissolving with sterile distilled water

Interior core

Exterior skinMiddle skin

Bacterial colonies of Staphylococcus aureus* and Escherichia coli* inoculated on nutrient agar gel media containing petri dishes

Agar gel disk diffusion method used to assess antibiotic efficacy

*Obtained from Carolina Biological Supply Company

The following disks* (5 in each dish) placed on petri dishes (n=7) with Staphylococcus aureus: Positive control: commercially available Penicillin,

Erythromycin disks Negative control: un-medicated dry and distilled water-

soaked disks Test: bitter melon extract-soaked disks (interior core,

middle skin and exterior skin).

*Obtained from Carolina Biological Supply Company

The following disks* (5 in each dish) placed on petri dishes (n=6) containing Escherichia coli: Positive control: commercially available Gentamicin disk Negative control: unmedicated dry and distilled water-

soaked disks Test: bitter melon extract-soaked disks.

*Obtained from Carolina Biological Supply Company

All petri dishes put inside an incubator at 37° C

After 24 hours of incubation petri dishes were taken out and clear zones of inhibition around the disks were measured

The whole experiment repeated on following day

Assessment of the mechanism of action of bitter melon against infection (bactericidal vs. bacteriostatic): Extracts mixed with the liquid microKwik culture vials*

containing Staphylococcus aureus (yellow) and Escherichia coli (white)

After 24 hour incubation at 37 °C, noted any color change of the media

*Obtained from Carolina Biological Supply Company

No clear zones of inhibition around bitter melon extract-soaked disks

Interior core

Middle skin

Exterior skin

Erythromycin

Penicillin

No clear zones of inhibition around bitter melon extract soaked disks

Inner skinMiddle skin

Exterior skinGentamicin

No color change in the bitter melon extract treated liquid microKwik culture vial containing Staphylococcus aureus (yellow) and Escherichia coli (white) after 24 hours of incubation at 37°C when compared to those vials without bitter melon extract

Bitter melon (Momordica charantia) does not have antibiotic properties when tested against Staphylococcus aureus and Eschericia coli

Removes the erroneous perception that eating bitter melon will prevent bacterial infections

Agar gel disk diffusion method (measuring clear zones of inhibition) used to determine presence of antibacterial property in bitter melon

For reproducibility of the data, repeated a second set of experiments following same methodology

Penicillin more potent Erythromycin against gram positive bacteria

Both negative and positive control improved quality of the study

Assessing the mechanism of bitter melon’s action against infection: No color change observed in the bitter melon extract

treated liquid microKwik culture vial containing Staphylococcus aureus and Escherichia coli after 24 hours of incubation

Further proof that bitter melon does not have any bactericidal action against those bacteria

Cannot completely rule out the presence of antibacterial compound in bitter melon as it may be in too minute a quantity to be picked up from the crude extract

Did not test other health benefits bitter melon may have in humans

No antibacterial action of bitter melon as proven by the lack of any zone of inhibition around bitter melon extract impregnated disks in Staphylococcus aureusand Escherichia coli colonies

No effect in the liquid microKwik culture vials after mixing with the bitter melon extract, thus disproving any bactericidal action

Even though bitter melon may not have antibacterial activity, this study does not disprove other health benefits this vegetable may have

Mrs. Berneice Boyle, Hathaway Brown School Hathaway Brown School Dr. Debabrata Ghosh, Associate Professor, Neurology

and Pediatrics, Nationwide Children’s Hospital and Ohio State Medical Center, Columbus, Ohio

Dr. Sudeshna Mitra, Pediatric Neurologist, Cleveland Clinic, Cleveland, Ohio

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